Cross-level fault detection and diagnosis of building HVAC systems

This paper presents a cross-level fault detection method. Two key features of the proposed method are 1) an energy description of all the units in an HVAC system and 2) a spatial–temporal partition strategy, which allows us to apply the FDD strategy to the entire building in a uniform manner. Energy flow models for HVAC units at all levels are presented. The concept of absolute and relative references for monitoring the energy performance is introduced. We have discussed the inherent complexity of HVAC systems, and proposed a grouping strategy of VAVs via correlation analysis. Examples of the temporal and spatial partitions are presented. Numerical examples are given to demonstrate the cross-level detection of two faults on AHU level and one fault on VAV level.